Stance control model in consideration of feed-forward control by reticulospinal tract

This paper aims to investigate the function of constant feed-forward control from the reticulospinal tract (RST) on improving posture stability during standing from the viewpoint of ability to countering the disturbances. We presented a stance control model considering not only the balance control, a PD controller, from vestibular tract based on vestibular feedback but also the constant feed-forward control u_r by reticulospinal tract. Parameters of PD controller, max muscle isometric force of back extensors and flexors and the constant strength of control from RST were optimized during a 3s forward dynamics simulation and the optimal u_r was obtained. Then, we fixed the value of u_r around the value of optimal one and only optimized other four parameters. After that, the abilities of countering the platform disturbance of the musculoskeletal (MSK) model under the control of different u_r were investigated. As a result, we found that optimal u_r would improve the posture stability and make MSK model more adaptive to the disturbance.